Labyrinth sealing device for an aircraft turbomachine

Abstract

A labyrinth-type sealing device for an aircraft turbomachine includes a rotor with at least one external annular lip. The device further includes a stator with an annular coating made of abradable material with extends around the lip and which is configured to cooperate in operation with the lip in order to form a labyrinth-type seal with respect to a flow of gas flowing through the rotor axially from upstream to downstream. The coating has an internal cylindrical surface that extends around the lip and is configured to contact the lip in order to form, by friction, an annular groove, and, upstream of the lip, a preformed annular slot.

The invention claimed is: 
     
         1 . A labyrinth-type sealing device for an aircraft turbomachine, the device comprising:
 a rotor having an axis of rotation and comprising external annular lips extending around said axis, and   a stator extending around the axis, this stator comprising an annular coating made of abradable material which extends around the lips and which is configured to cooperate in operation with the lips to form a labyrinth-type seal with respect to a flow of gas which is intended to flow axially from upstream to downstream through the rotor, the coating comprising an internal cylindrical surface extending around the lips and which is configured to contact the lips to form annular grooves extending around the axis by friction,   wherein the surface comprises, upstream of each of the lips, a preformed annular slot which extends around the axis and which is configured to receive said lip in the event of axial upstream displacement of the rotor with respect to the stator, a number of preformed slots being equal to a number of lips of the rotor.   
     
     
         2 . The device according to  claim 1 , wherein the rotor comprises at least one upstream lip and one downstream lip, the upstream and downstream lips being surrounded by a same cylindrical surface of the coating or by two distinct cylindrical surfaces, respectively upstream and downstream, of the coating. 
     
     
         3 . The device according to  claim 2 , wherein:
 in the case where the upstream and downstream lips are surrounded by the same cylindrical surface of the coating, the cylindrical surface comprises a preformed slot upstream of the upstream lip, and/or a preformed slot upstream of the downstream lip, or   in the case where the upstream and downstream lips are surrounded by two distinct cylindrical surfaces, respectively upstream and downstream of the coating, the upstream cylindrical surface comprises a preformed slot upstream of the upstream lip, and/or the downstream cylindrical surface comprises a preformed slot upstream of the downstream lip.   
     
     
         4 . The device according to  claim 2 , wherein the upstream and downstream cylindrical surfaces are stepped and comprise different diameters. 
     
     
         5 . The device according to  claim 4 , wherein the slot is interposed axially between the two cylindrical surfaces. 
     
     
         6 . The device according to  claim 1 , wherein each slot is located at an axial distance (L 1 ) upstream of a corresponding lip, which is less than or equal to half the axial distance (L 2 ) between the two lips. 
     
     
         7 . The device according to  claim 1 , wherein each slot is located at an axial distance (L 1 ) upstream of a corresponding lip, which is greater than half the axial distance (L 2 ) between the two lips. 
     
     
         8 . The device according to  claim 6 , wherein said axial distance (L 1 ) is between 1 and 20 mm. 
     
     
         9 . The device according to  claim 1 , wherein each slot has a radial depth or dimension (H 1 ) less than or equal to a radial thickness or dimension of a zone of the coating in which this slot is formed. 
     
     
         10 . The device according to  claim 1 , wherein each slot has an axial dimension (E 1 ) greater than or equal to half an axial thickness (E 2 ) of a corresponding lip, the thickness being measured at a level of an external periphery of this lip. 
     
     
         11 . The device according to  claim 1 , wherein each slot is located at an axial distance from an upstream axial end of the cylindrical surface in which that slot is formed. 
     
     
         12 . The device according to  claim 1 , wherein the rotor is a compressor or turbine blading, and the stator is a sealing ring carried by a casing of the compressor or turbine. 
     
     
         13 . An aircraft turbomachine, comprising at least one of the device according to  claim 1 . 
     
     
         14 . The device according to  claim 8 , wherein said axial distance (L 1 ) is between 1 and 5 mm.